The present disclosure relates to a power conversion device and a method of controlling the same.
An exemplary power conversion device which converts and outputs a characteristic of input power is a DC-DC converter. It is known that when a constituent material of a switching element used in a step-up circuit or the like of a DC-DC converter is replaced with a wide band gap (WBG) semiconductor such as a nitride-based semiconductor (e.g., GaN-based semiconductor), there are advantages that a switching element can be downsized and has a low loss, for example. Additionally, as for a semiconductor device formed of the GaN-based semiconductor, a normally-on type has better switching performance than a normally-off type does. For example, it is known that a high-performance product can be relatively easily manufactured at low cost because the normally-on type has gate capacity smaller than the normally-off type does, also can reduce on-resistance, and can achieve high-speed switching operation.
However, in the case of using the normally-on type GaN-based semiconductor device as a switching element of a power conversion device, a high current may flow between a drain and a source of the switching element when a failure occurs at a gate drive unit thereof, and the failure may be further expanded in terms of an area and a level.
To prevent the switching element from high current flow, disclosed is a configuration in which a protection device is provided on an upstream side of a power conversion device (see, for example, Japanese Patent No. 5567508).